re-building a time history signal from a rainflow matrix

[jayjaychina]

I would like to reduce a time history signal. Then I performed a rainflow matrix. I can reduce this matrix by selecting bigger amplitudes. Then I would need to re-build a time history signal from this matrix : it will be a sum of sinus, but it is very boring to build one part by one. Thanks a lot for your help. 

[chat-relotte]

Hello,

Can you be clearer on what is your question so that I can try to help you ?

Thanks in advance,

[Brad_Turpin]

Hi jayjaychina,

I forwarded your question to the developers responsible for the Rainflow analysis function in DIAdem, and they said that what you're asking for is not possible with our implementation.

Sorry,

Brad Turpin

DIAdem Product Support Engineer
National Instruments

[jayjaychina]

thanks for answer,

Is there a way to reduce a time history by cutting small amplitudes and then to keep for exemple 20% of a signal with only biggest peaks ?

F.Lemoine

[Brad_Turpin]

Hi jayjaychina,

Sure, that would work.  You'd likely end up with data exerpts that would be inconsistently placed on the X axis in time.  That's not a problem for graphing in DIAdem, but there are some ANALYSIS functions that require a constant time base.  The real question is how you want to define the data to keep and the data to delete.  In LabVIEW-DSC they set up a "dead-band" of values on the Y axis that define data you're NOT interested in, then only data outside (below or above) the dead-band actually get logged.  You could easily do something like that in DIAdem on already acquired data to reduce it, but there are many other schemes you could apply as well.  DIAdem has built-in data reduction functions based on sampling intervals, but it sounds like you want something much more customized than that.

Brad Turpin

DIAdem Product Support Engineer
National Instruments